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2.
Elife ; 102021 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-33890575

RESUMO

Mechanical stress during cell migration may be a previously unappreciated source of genome instability, but the extent to which this happens in any animal in vivo remains unknown. We consider an in vivo system where the adult stem cells of planarian flatworms are required to migrate to a distal wound site. We observe a relationship between adult stem cell migration and ongoing DNA damage and repair during tissue regeneration. Migrating planarian stem cells undergo changes in nuclear shape and exhibit increased levels of DNA damage. Increased DNA damage levels reduce once stem cells reach the wound site. Stem cells in which DNA damage is induced prior to wounding take longer to initiate migration and migrating stem cell populations are more sensitive to further DNA damage than stationary stem cells. RNAi-mediated knockdown of DNA repair pathway components blocks normal stem cell migration, confirming that active DNA repair pathways are required to allow successful migration to a distal wound site. Together these findings provide evidence that levels of migration-coupled-DNA-damage are significant in adult stem cells and that ongoing migration requires DNA repair mechanisms. Our findings reveal that migration of normal stem cells in vivo represents an unappreciated source of damage, which could be a significant source of mutations in animals during development or during long-term tissue homeostasis.


Assuntos
Células-Tronco Adultas/patologia , Movimento Celular , Dano ao DNA , Reparo do DNA , Planárias , Cicatrização , Células-Tronco Adultas/metabolismo , Células-Tronco Adultas/efeitos da radiação , Animais , Movimento Celular/efeitos da radiação , Forma do Núcleo Celular , Regulação da Expressão Gênica , Instabilidade Genômica , Cinética , Planárias/genética , Planárias/metabolismo , Planárias/efeitos da radiação , Estresse Mecânico , Cicatrização/efeitos da radiação
3.
J Invest Dermatol ; 141(3): 638-647.e13, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32800877

RESUMO

In repigmentation of human vitiligo, the melanocyte (MC) precursors in the hair follicle bulge proliferate, migrate, and differentiate to repopulate the depigmented epidermis. Here, we present a comprehensive characterization of pathways and signals in the bulge that control the repigmentation process. Using biopsies from patients with vitiligo, we have selectively harvested, by laser capture microdissection, MC and keratinocyte precursors from the hair follicle bulge of untreated vitiligo skin and vitiligo skin treated with narrow-band UVB. The captured material was subjected to whole transcriptome RNA-sequencing. With this strategy, we found that repigmentation in the bulge MC precursors is driven by KCTD10, a signal with unknown roles in the skin, and CTNNB1 (encoding ß-catenin) and RHO guanosine triphosphatase [RHO GTPase, RHO], two signaling pathways previously shown to be involved in pigmentation biology. Knockdown studies in cultured human MCs of RHOJ, the upmost differentially expressed RHO family component, corroborated with our findings in patients with vitiligo, identified RHOJ involvement in UV response and melanization, and confirmed previously identified roles in melanocytic cell migration and apoptosis. A better understanding of mechanisms that govern repigmentation in MC precursors will enable the discovery of molecules that induce robust repigmentation phenotypes in vitiligo.


Assuntos
Células-Tronco Adultas/metabolismo , Melanócitos/metabolismo , Pigmentação da Pele/efeitos da radiação , Terapia Ultravioleta , Vitiligo/terapia , Adolescente , Adulto , Células-Tronco Adultas/efeitos da radiação , Idoso , Criança , Feminino , Folículo Piloso/citologia , Folículo Piloso/metabolismo , Folículo Piloso/patologia , Folículo Piloso/efeitos da radiação , Humanos , Queratinócitos/metabolismo , Queratinócitos/efeitos da radiação , Masculino , Melanócitos/efeitos da radiação , Pessoa de Meia-Idade , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , RNA-Seq , Transdução de Sinais/efeitos da radiação , Resultado do Tratamento , Vitiligo/patologia , Adulto Jovem , beta Catenina/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo
4.
Sci Rep ; 10(1): 19080, 2020 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-33154387

RESUMO

Exposure to genotoxic stress by environmental agents or treatments, such as radiation therapy, can diminish healthspan and accelerate aging. We have developed a Drosophila melanogaster model to study the molecular effects of radiation-induced damage and repair. Utilizing a quantitative intestinal permeability assay, we performed an unbiased GWAS screen (using 156 strains from the Drosophila Genetic Reference Panel) to search for natural genetic variants that regulate radiation-induced gut permeability in adult D. melanogaster. From this screen, we identified an RNA binding protein, Musashi (msi), as one of the possible genes associated with changes in intestinal permeability upon radiation. The overexpression of msi promoted intestinal stem cell proliferation, which increased survival after irradiation and rescued radiation-induced intestinal permeability. In summary, we have established D. melanogaster as an expedient model system to study the effects of radiation-induced damage to the intestine in adults and have identified msi as a potential therapeutic target.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Drosophila melanogaster/efeitos da radiação , Proteínas de Ligação a RNA/genética , Células-Tronco Adultas/fisiologia , Células-Tronco Adultas/efeitos da radiação , Animais , Morte Celular/efeitos da radiação , Proliferação de Células/efeitos da radiação , Dano ao DNA , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/fisiologia , Feminino , Expressão Gênica/efeitos da radiação , Genes de Insetos/efeitos da radiação , Estudo de Associação Genômica Ampla , Intestinos/citologia , Intestinos/fisiologia , Intestinos/efeitos da radiação , Locomoção/efeitos da radiação , Permeabilidade/efeitos da radiação , Proteínas de Ligação a RNA/fisiologia , Lesões Experimentais por Radiação/genética , Lesões Experimentais por Radiação/patologia , Lesões Experimentais por Radiação/fisiopatologia
5.
J Invest Dermatol ; 140(9): 1691-1697, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32800183

RESUMO

Human skin acts as a barrier to protect our bodies from UV rays and external pathogens and to prevent water loss. Phenotypes of aging, or natural aging due to chronic damage, include wrinkles and the reduction of skin thickness that occur because of a loss of skin cell function. The dysregulation of autophagy, a lysosome-related degradation pathway, can lead to cell senescence, cancer, and various human diseases due to abnormal cellular homeostasis. Here, we discuss the roles and molecular mechanisms of autophagy involved in the anti-aging effects of autophagy and the relationship between autophagy and aging in skin cells.


Assuntos
Autofagia/fisiologia , Envelhecimento da Pele/fisiologia , Dermatopatias/fisiopatologia , Pele/citologia , Células-Tronco Adultas/fisiologia , Células-Tronco Adultas/efeitos da radiação , Senescência Celular/fisiologia , Senescência Celular/efeitos da radiação , Fibroblastos/fisiologia , Fibroblastos/efeitos da radiação , Humanos , Queratinócitos/fisiologia , Queratinócitos/efeitos da radiação , Melanócitos/fisiologia , Melanócitos/efeitos da radiação , Pele/efeitos da radiação , Envelhecimento da Pele/efeitos da radiação , Dermatopatias/etiologia , Raios Ultravioleta/efeitos adversos , Perda Insensível de Água/fisiologia , Perda Insensível de Água/efeitos da radiação
6.
Cell Mol Gastroenterol Hepatol ; 9(4): 587-609, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31778829

RESUMO

BACKGROUND & AIMS: Self-renewal and multipotent differentiation are cardinal properties of intestinal stem cells (ISCs), mediated in part by WNT and NOTCH signaling. Although these pathways are well characterized, the molecular mechanisms that control the 'stemness' of ISCs are still not well defined. Here, we investigated the role of Krüppel-like factor 5 (KLF5) in regulating ISC functions. METHODS: We performed studies in adult Lgr5EGFP-IRES-creERT2;Rosa26LSLtdTomato (Lgr5Ctrl) and Lgr5EGFP-IRES-creERT2;Klf5fl/fl;Rosa26LSLtdTomato (Lgr5ΔKlf5) mice. Mice were injected with tamoxifen to activate Cre recombinase, which deletes Klf5 from the intestinal epithelium in Lgr5ΔKlf5 but not Lgr5Crtl mice. In experiments involving irradiation, mice were subjected to 12 Gy total body irradiation (TBI). Tissues were collected for immunofluorescence (IF) analysis and next generation sequencing. Oganoids were derived from fluoresecence activated cell sorted- (FACS-) single cells from tamoxifen-treated Lgr5ΔKlf5 or Lgr5Crtl mice and examined by immunofluorescence stain. RESULTS: Lgr5+ ISCs lacking KLF5 proliferate faster than control ISCs but fail to self-renew, resulting in a depleted ISC compartment. Transcriptome analysis revealed that Klf5-null Lgr5+ cells lose ISC identity and prematurely differentiate. Following irradiation injury, which depletes Lgr5+ ISCs, reserve Klf5-null progenitor cells fail to dedifferentiate and regenerate the epithelium. Absence of KLF5 inactivates numerous selected enhancer elements and direct transcriptional targets including canonical WNT- and NOTCH-responsive genes. Analysis of human intestinal tissues showed increased levels of KLF5 in the regenerating epithelium as compared to those of healthy controls. CONCLUSION: We conclude that ISC self-renewal, lineage specification, and precursor dedifferentiation require KLF5, by its ability to regulate epigenetic and transcriptional activities of ISC-specific gene sets. These findings have the potential for modulating ISC functions by targeting KLF5 in the intestinal epithelium.


Assuntos
Células-Tronco Adultas/fisiologia , Mucosa Intestinal/fisiologia , Fatores de Transcrição Kruppel-Like/metabolismo , Lesões por Radiação/patologia , Regeneração/genética , Células-Tronco Adultas/efeitos da radiação , Animais , Estudos de Casos e Controles , Linhagem da Célula/genética , Autorrenovação Celular/genética , Células Cultivadas , Colite/etiologia , Colite/patologia , Neoplasias Colorretais/patologia , Neoplasias Colorretais/terapia , Modelos Animais de Doenças , Enterite/etiologia , Enterite/patologia , Epigênese Genética , Feminino , Humanos , Mucosa Intestinal/citologia , Mucosa Intestinal/efeitos da radiação , Fatores de Transcrição Kruppel-Like/análise , Fatores de Transcrição Kruppel-Like/genética , Masculino , Camundongos , Camundongos Transgênicos , Organoides , Cultura Primária de Células , RNA-Seq , Receptores Acoplados a Proteínas G/genética , Ativação Transcricional , Irradiação Corporal Total , Via de Sinalização Wnt/genética
7.
DNA Repair (Amst) ; 76: 70-75, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30822688

RESUMO

Radiosusceptibility is the sensitivity of a biological organism to ionising radiation (IR)-induced carcinogenesis, an outcome of IR exposure relevant following low doses. The tissue response is strongly influenced by the DNA damage response (DDR) activated in stem and progenitor cells. We previously reported that in vivo exposure to 2 Gy X-rays activates apoptosis, proliferation arrest and premature differentiation in neural progenitor cells (transit amplifying cells and neuroblasts) but not in neural stem cells (NSCs) of the largest neurogenic region of the adult brain, the subventricular zone (SVZ). These responses promote adult quiescent NSC (qNSC) activation after 2 Gy. In contrast, neonatal (P5) SVZ neural progenitors continue proliferating and do not activate qNSCs. Significantly, the human and mouse neonatal brain is radiosusceptible. Here, we examine the response of stem and progenitor cells in the SVZ to low IR doses (50-500 mGy). We observe a linear dose-response for apoptosis but, in contrast, proliferation arrest and neuroblast differentiation require a threshold dose of 200 or 500 mGy, respectively. Importantly, qNSCs were not activated at doses below 500 mGy. Thus, full DDR activation in the neural stem cell compartment in vivo necessitates a threshold dose, which can be considered of significance when evaluating IR-induced cancer risk and dose extrapolation.


Assuntos
Células-Tronco Adultas/citologia , Células-Tronco Adultas/efeitos da radiação , Células-Tronco Neurais/citologia , Células-Tronco Neurais/efeitos da radiação , Animais , Proliferação de Células/efeitos da radiação , Relação Dose-Resposta à Radiação , Camundongos
8.
Clin Cancer Res ; 24(24): 6583-6593, 2018 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-30135147

RESUMO

PURPOSE: Radiotherapy for head and neck cancer may result in serious side effects, such as hyposalivation, impairing the patient's quality of life. Modern radiotherapy techniques attempt to reduce the dose to salivary glands, which, however, results in low-dose irradiation of the tissue stem cells. Here we assess the low-dose sensitivity of tissue stem cells and the consequences for tissue function. EXPERIMENTAL DESIGN: Postirradiation rat salivary gland secretory function was determined after pilocarpine induction. Murine and patient-derived salivary gland and thyroid gland organoids were irradiated and clonogenic survival was assessed. The DNA damage response (DDR) was analyzed in organoids and modulated using different radiation modalities, chemical inhibition, and genetic modification. RESULTS: Relative low-dose irradiation to the high-density stem cell region of rat salivary gland disproportionally impaired function. Hyper-radiosensitivity at doses <1 Gy, followed by relative radioresistance at doses ≥1 Gy, was observed in salivary gland and thyroid gland organoid cultures. DDR modulation resulted in diminished, or even abrogated, relative radioresistance. Furthermore, inhibition of the DDR protein ATM impaired DNA repair after 1 Gy, but not 0.25 Gy. Irradiation of patient-derived salivary gland organoid cells showed similar responses, whereas a single 1 Gy dose to salivary gland-derived stem cells resulted in greater survival than clinically relevant fractionated doses of 4 × 0.25 Gy. CONCLUSIONS: We show that murine and human glandular tissue stem cells exhibit a dose threshold in DDR activation, resulting in low-dose hyper-radiosensitivity, with clinical implications in radiotherapy treatment planning. Furthermore, our results from patient-derived organoids highlight the potential of organoids to study normal tissue responses to radiation.


Assuntos
Células-Tronco Adultas/metabolismo , Células-Tronco Adultas/efeitos da radiação , Dano ao DNA/efeitos da radiação , Suscetibilidade a Doenças , Doses de Radiação , Radiação Ionizante , Animais , Relação Dose-Resposta à Radiação , Imunofluorescência , Humanos , Masculino , Camundongos , Camundongos Knockout , Ratos
9.
Stem Cell Reports ; 11(2): 565-577, 2018 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-29983386

RESUMO

Deciphering the mechanisms that regulate the quiescence of adult neural stem cells (NSCs) is crucial for the development of therapeutic strategies based on the stimulation of their endogenous regenerative potential in the damaged brain. We show that LeXbright cells sorted from the adult mouse subventricular zone exhibit all the characteristic features of quiescent NSCs. Indeed, they constitute a subpopulation of slowly dividing cells that is able to enter the cell cycle to regenerate the irradiated niche. Comparative transcriptomic analyses showed that they express hallmarks of NSCs but display a distinct molecular signature from activated NSCs (LeX+EGFR+ cells). Particularly, numerous membrane receptors are expressed on quiescent NSCs. We further revealed a different expression pattern of Syndecan-1 between quiescent and activated NSCs and demonstrated its role in the proliferation of activated NSCs. Our data highlight the central role of the stem cell microenvironment in the regulation of quiescence in adult neurogenic niches.


Assuntos
Células-Tronco Adultas/citologia , Células-Tronco Adultas/metabolismo , Ciclo Celular , Diferenciação Celular , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Nicho de Células-Tronco , Células-Tronco Adultas/efeitos da radiação , Ciclo Celular/genética , Ciclo Celular/efeitos da radiação , Diferenciação Celular/genética , Diferenciação Celular/efeitos da radiação , Metabolismo Energético , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Células-Tronco Neurais/efeitos da radiação , Neurogênese , Estresse Oxidativo , Transdução de Sinais , Nicho de Células-Tronco/genética , Nicho de Células-Tronco/efeitos da radiação
10.
Int J Mol Sci ; 19(7)2018 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-29986519

RESUMO

Within their niche, adipose-derived stem cells (ADSCs) are essential for homeostasis as well as for regeneration. Therefore, the interest of physicians is to use ADSCs as a tool for radiation oncology and regenerative medicine. To investigate related risks, this study analyses the radiation response of adult stem cells isolated from the adipose tissue of the female breast. To avoid donor-specific effects, ADSCs isolated from breast reduction mammoplasties of 10 donors were pooled and used for the radiobiological analysis. The clonogenic survival fraction assay was used to classify the radiation sensitivity in comparison to a more radiation-sensitive (ZR-75-1), moderately sensitive (MCF-7), and resistant (MCF10A) cell lines. Afterwards, cytotoxicity and genotoxicity of irradiation on ADSCs were investigated. On the basis of clonogenic cell survival rates of ADSCs after irradiation, we assign ADSCs an intermediate radiation sensitivity. Furthermore, a high repair capacity of double-strand breaks is related to an altered cell cycle arrest and increased expression of cyclin-dependent kinase (CDK) inhibitor p21. ADSCs isolated from breast tissue exhibit intermediate radiation sensitivity, caused by functional repair mechanisms. Therefore, we propose ADSCs to be a promising tool in radiation oncology.


Assuntos
Tecido Adiposo/citologia , Células-Tronco Adultas/citologia , Mama/citologia , Inibidor de Quinase Dependente de Ciclina p21/genética , Tolerância a Radiação , Regulação para Cima , Tecido Adiposo/efeitos da radiação , Células-Tronco Adultas/efeitos da radiação , Mama/efeitos da radiação , Pontos de Checagem do Ciclo Celular/efeitos da radiação , Linhagem Celular , Sobrevivência Celular/efeitos da radiação , Feminino , Regulação da Expressão Gênica/efeitos da radiação , Humanos , Células MCF-7 , Mamoplastia , Nicho de Células-Tronco/efeitos da radiação
11.
Sci Rep ; 8(1): 2057, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29391502

RESUMO

Low power light (LPL) treatment has been widely used in various clinical trials, which has been known to reduce pain and inflammation and to promote wound healing. LPL was also shown to enhance differentiation of stem cells into specific lineages. However, most studies have used high power light in mW order, and there was lack of studies about the effects of very low power light in µW. In this study, we applied 810 nm LPL of 128 µW/cm2 energy density in vitro. Upon this value, continuous wave (CW) irradiation did not induce any significant changes for differentiation of human dental pulp stem cells (hDPSCs). However, the membrane hyperpolarization, alkaline phosphatase activity, and intracellular oxidative stress were largely enhanced in the pulsed wave (PW) with 30% of duty cycle and 300-3000 Hz frequencies-LPL in which LED driver work in the form of square wave. After 21 days of daily LPL treatment, Western blot revealed the dentinogenesis in this condition in vitro. This study demonstrates that the very low power light at 810 nm enhanced significant differentiation of hDPSCs in the PW mode and there were duty cycle dependency as well as pulsing frequency dependency in the efficiency.


Assuntos
Células-Tronco Adultas/citologia , Polpa Dentária/citologia , Dentinogênese , Luz , Fototerapia/métodos , Células-Tronco Adultas/efeitos da radiação , Células Cultivadas , Polpa Dentária/efeitos da radiação , Humanos , Fototerapia/instrumentação
12.
Sci Rep ; 8(1): 2072, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29391546

RESUMO

Total body irradiation (TBI) leads to dose- and tissue-specific lethality. In the current study, we demonstrate that a mitochondrion-targeted nitroxide JP4-039 given once 24 hours after 9-10 Gy TBI significantly improves mouse survival, and the recovery of intestinal barrier, differentiation and stem cell functions. The GI-protective effects are associated with rapid and selective induction of tight junction proteins and cytokines including TGF-ß, IL-10, IL-17a, IL-22 and Notch signaling long before bone marrow depletion. However, no change was observed in crypt death or the expression of prototypic pro-inflammatory cytokines such as TNF-α, IL-6 or IL-1ß. Surprisingly, bone marrow transplantation (BMT) performed 24 hours after TBI improves intestinal barrier and stem cell recovery with induction of IL-10, IL-17a, IL-22, and Notch signaling. Further, BMT-rescued TBI survivors display increased intestinal permeability, impaired ISC function and proliferation, but not obvious intestinal inflammation or increased epithelial death. These findings identify intestinal epithelium as a novel target of radiation mitigation, and potential strategies to enhance ISC recovery and regeneration after accidental or medical exposures.


Assuntos
Síndrome Aguda da Radiação/tratamento farmacológico , Células-Tronco Adultas/efeitos da radiação , Mucosa Intestinal/efeitos da radiação , Óxidos de Nitrogênio/farmacologia , Protetores contra Radiação/farmacologia , Síndrome Aguda da Radiação/terapia , Células-Tronco Adultas/citologia , Células-Tronco Adultas/fisiologia , Animais , Transplante de Medula Óssea , Diferenciação Celular , Proliferação de Células , Citocinas/metabolismo , Feminino , Mucosa Intestinal/citologia , Camundongos , Camundongos Endogâmicos C57BL , Óxidos de Nitrogênio/uso terapêutico , Protetores contra Radiação/uso terapêutico , Proteínas de Junções Íntimas/metabolismo
13.
Ann Hematol ; 97(4): 697-707, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29349655

RESUMO

Total body irradiation (TBI) is frequently used in hematopoietic stem cell transplantation (HSCT) and is associated with many complications due to radiation injury to the normal cells, including normal stem cells. Nevertheless, the effects of TBI on the mesenchymal stromal stem cell (MSC) are not fully understood. Bone marrow-derived MSCs (BM-MSCs) isolated from normal adults were irradiated with 200 cGy twice daily for consecutive 3 days, a regimen identical to that used in TBI-conditioning HSCT. The characteristics, differentiation potential, cytogenetics, hematopoiesis-supporting function, and carcinogenicity of the irradiated BM-MSCs were then compared to the non-irradiated control. The irradiated and non-irradiated MSCs shared similar morphology, phenotype, and hematopoiesis-supporting function. However, irradiated MSCs showed much lower proliferative and differentiative potential. Irradiation also induced clonal cytogenetic abnormalities of MSCs. Nevertheless, the carcinogenicity of irradiated MSCs is low in vitro and in vivo. In parallel with the ex vivo irradiation experiments, decreased proliferative and differentiative abilities and clonal cytogenetic abnormalities can also be found in MSCs isolated from transplant recipients who had received TBI-based conditioning previously. Thus, TBI used in HSCT drastically injury MSCs and may contribute to the development of some long-term complications associated with clonal cytogenetic abnormality and poor adipogenesis and osteogenesis after TBI.


Assuntos
Apoptose/efeitos da radiação , Células da Medula Óssea/efeitos da radiação , Aberrações Cromossômicas/efeitos da radiação , Células-Tronco Hematopoéticas/efeitos da radiação , Células-Tronco Mesenquimais/efeitos da radiação , Lesões por Radiação/patologia , Irradiação Corporal Total/efeitos adversos , Adulto , Células-Tronco Adultas/efeitos da radiação , Células da Medula Óssea/citologia , Células da Medula Óssea/patologia , Diferenciação Celular/efeitos da radiação , Proliferação de Células/efeitos da radiação , Células Cultivadas , China , Transtornos Cromossômicos/etiologia , Transtornos Cromossômicos/patologia , Feminino , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/patologia , Hospitais Universitários , Humanos , Leucemia/patologia , Leucemia/terapia , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/patologia , Necrose , Lesões por Radiação/etiologia , Condicionamento Pré-Transplante/efeitos adversos , Células Tumorais Cultivadas , Adulto Jovem
14.
Diabetes ; 67(2): 291-298, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29167189

RESUMO

Previous studies demonstrated that brief (3 to 4 min) daily application of light at 670 nm to diabetic rodents inhibited molecular and pathophysiologic processes implicated in the pathogenesis of diabetic retinopathy (DR) and reversed diabetic macular edema in small numbers of patients studied. Whether or not this therapy would inhibit the neural and vascular lesions that characterize the early stages of the retinopathy was unknown. We administered photobiomodulation (PBM) therapy daily for 8 months to streptozotocin-diabetic mice and assessed effects of PBM on visual function, retinal capillary permeability, and capillary degeneration using published methods. Vitamin D receptor and Cyp24a1 transcripts were quantified by quantitative real-time PCR, and the abundance of c-Kit+ stem cells in blood and retina were assessed. Long-term daily administration of PBM significantly inhibited the diabetes-induced leakage and degeneration of retinal capillaries and also significantly inhibited the diabetes-induced reduction in visual function. PBM also inhibited diabetes-induced reductions in retinal Cyp24a1 mRNA levels and numbers of circulating stem cells (CD45-/c-Kit+), but these effects may not account for the beneficial effects of PBM on the retinopathy. PBM significantly inhibits the functional and histopathologic features of early DR, and these effects likely are mediated via multiple mechanisms.


Assuntos
Permeabilidade Capilar/efeitos da radiação , Retinopatia Diabética/terapia , Terapia com Luz de Baixa Intensidade , Neurônios/efeitos da radiação , Retina/efeitos da radiação , Vasos Retinianos/efeitos da radiação , Visão Ocular/efeitos da radiação , Células-Tronco Adultas/metabolismo , Células-Tronco Adultas/patologia , Células-Tronco Adultas/efeitos da radiação , Animais , Biomarcadores/sangue , Biomarcadores/metabolismo , Diabetes Mellitus Experimental/complicações , Retinopatia Diabética/metabolismo , Retinopatia Diabética/patologia , Retinopatia Diabética/fisiopatologia , Progressão da Doença , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Regulação da Expressão Gênica/efeitos da radiação , Processamento de Imagem Assistida por Computador , Terapia com Luz de Baixa Intensidade/efeitos adversos , Masculino , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , Proteínas do Tecido Nervoso , Neurônios/metabolismo , Neurônios/patologia , Receptores de Calcitriol/genética , Receptores de Calcitriol/metabolismo , Retina/metabolismo , Retina/patologia , Retina/fisiopatologia , Vasos Retinianos/metabolismo , Vasos Retinianos/patologia , Vasos Retinianos/fisiopatologia , Estreptozocina , Vitamina D3 24-Hidroxilase/genética , Vitamina D3 24-Hidroxilase/metabolismo
15.
Development ; 144(19): 3440-3453, 2017 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-28893948

RESUMO

Migration of stem cells underpins the physiology of metazoan animals. For tissues to be maintained, stem cells and their progeny must migrate and differentiate in the correct positions. This need is even more acute after tissue damage by wounding or pathogenic infection. Inappropriate migration also underpins metastasis. Despite this, few mechanistic studies address stem cell migration during repair or homeostasis in adult tissues. Here, we present a shielded X-ray irradiation assay that allows us to follow stem cell migration in planarians. We demonstrate the use of this system to study the molecular control of stem cell migration and show that snail-1, snail-2 and zeb-1 EMT transcription factor homologs are necessary for cell migration to wound sites and for the establishment of migratory cell morphology. We also observed that stem cells undergo homeostatic migration to anterior regions that lack local stem cells, in the absence of injury, maintaining tissue homeostasis. This requires the polarity determinant notum Our work establishes planarians as a suitable model for further in-depth study of the processes controlling stem cell migration in vivo.


Assuntos
Células-Tronco Adultas/citologia , Movimento Celular , Transição Epitelial-Mesenquimal , Planárias/citologia , Planárias/metabolismo , Células-Tronco Pluripotentes/citologia , Fatores de Transcrição/metabolismo , Células-Tronco Adultas/metabolismo , Células-Tronco Adultas/efeitos da radiação , Animais , Linhagem da Célula/efeitos da radiação , Movimento Celular/efeitos da radiação , Forma Celular/efeitos da radiação , Sequência Conservada , Células Epidérmicas , Transição Epitelial-Mesenquimal/efeitos da radiação , Cadeias beta de Integrinas/metabolismo , Metaloproteinases da Matriz/metabolismo , Planárias/genética , Células-Tronco Pluripotentes/efeitos da radiação , Fatores de Transcrição da Família Snail/metabolismo , Raios X
16.
Sci Rep ; 7(1): 10948, 2017 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-28887547

RESUMO

Magnetotherapy has been receiving increased attention as an attractive strategy for modulating cell physiology directly at the site of injury, thereby providing the medical community with a safe and non-invasive therapy. Yet, how magnetic field influences tendon cells both at the cellular and molecular levels remains unclear. Thus, the influence of a low-frequency static magnetic field (2 Hz, 350 mT) on human tendon-derived cells was studied using different exposure times (4 and 8 h; short-term studies) and different regimens of exposure to an 8h-period of magnetic stimulation (continuous, every 24 h or every 48 h; long-term studies). Herein, 8 h stimulation in short-term studies significantly upregulated the expression of tendon-associated genes SCX, COL1A1, TNC and DCN (p < 0.05) and altered intracellular Ca2+ levels (p < 0.05). Additionally, every 24 h regimen of stimulation significantly upregulated COL1A1, COL3A1 and TNC at day 14 in comparison to control (p < 0.05), whereas continuous exposure differentially regulated the release of the immunomodulatory cytokines IL-1ß and IL-10 (p < 0.001) but only at day 7 in comparison to controls. Altogether, these results provide new insights on how low-frequency static magnetic field fine-tune the behaviour of tendon cells according to the magnetic settings used, which we foresee to represent an interesting candidate to guide tendon regeneration.


Assuntos
Campos Magnéticos , Tendões/efeitos da radiação , Adulto , Células-Tronco Adultas/metabolismo , Células-Tronco Adultas/efeitos da radiação , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Cálcio/metabolismo , Células Cultivadas , Colágeno Tipo I/metabolismo , Cadeia alfa 1 do Colágeno Tipo I , Citocinas/metabolismo , Decorina/metabolismo , Humanos , Masculino , Mecanotransdução Celular , Regeneração , Tenascina/metabolismo , Tendões/citologia , Tendões/metabolismo
17.
Brain Res Bull ; 132: 150-159, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28552674

RESUMO

Birth of new neurons in the hippocampus persists in the brain of adult mammals and critically underpins optimal learning and memory. The process of adult neurogenesis is significantly reduced following brain irradiation and this correlates with impaired cognitive function. In this study, we aimed to compare the long-term effects of two environmental paradigms (i.e. enriched environment and exercise) on adult neurogenesis following high-dose (10Gy) total body irradiation. When housed in standard (sedentary) conditions, irradiated mice revealed a long-lasting (up to 4 months) deficit in neurogenesis in the granule cell layer of the dentate gyrus, the region that harbors the neurogenic niche. This depressive effect of total body irradiation on adult neurogenesis was partially alleviated by exposure to enriched environment but not voluntary exercise, where mice were single-housed with unlimited access to a running wheel. Exposure to voluntary exercise, but not enriched environment, did lead to significant increases in microglia density in the granule cell layer of the hippocampus; our study shows that these changes result from local microglia proliferation rather than recruitment and infiltration of circulating Cx3cr1+/gfp blood monocytes that subsequently differentiate into microglia-like cells. In summary, latent neural precursor cells remain present in the neurogenic niche of the adult hippocampus up to 8 weeks following high-dose total body irradiation. Environmental enrichment can partially restore the adult neurogenic process in this part of the brain following high-dose irradiation, and this was found to be independent of blood monocyte-derived microglia presence.


Assuntos
Meio Ambiente , Hipocampo/fisiopatologia , Hipocampo/efeitos da radiação , Neurogênese , Corrida , Irradiação Corporal Total/efeitos adversos , Células-Tronco Adultas/patologia , Células-Tronco Adultas/fisiologia , Células-Tronco Adultas/efeitos da radiação , Animais , Receptor 1 de Quimiocina CX3C/genética , Receptor 1 de Quimiocina CX3C/metabolismo , Hipocampo/patologia , Abrigo para Animais , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Microglia/patologia , Microglia/fisiologia , Microglia/efeitos da radiação , Monócitos/patologia , Monócitos/fisiologia , Monócitos/efeitos da radiação , Células-Tronco Neurais/patologia , Células-Tronco Neurais/fisiologia , Células-Tronco Neurais/efeitos da radiação , Neurogênese/fisiologia , Neurogênese/efeitos da radiação , Doses de Radiação , Distribuição Aleatória , Corrida/fisiologia , Comportamento Sedentário , Volição
18.
J Radiat Res ; 58(5): 636-646, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28340212

RESUMO

Accidental high-dose radiation exposures can lead to multi-organ injuries, including radiation dermatitis. The types of cellular damage leading to radiation dermatitis are not completely understood. To identify the cellular mechanisms that underlie radiation-induced skin injury in vivo, we evaluated the time-course of cellular effects of radiation (14, 16 or 17 Gy X-rays; 0.5 Gy/min) in the skin of C57BL/6 mice. Irradiation of 14 Gy induced mild inflammation, observed histologically, but no visible hair loss or erythema. However, 16 or 17 Gy radiation induced dry desquamation, erythema and mild ulceration, detectable within 14 days post-irradiation. Histological evaluation revealed inflammation with mast cell infiltration within 14 days. Fibrosis occurred 80 days following 17 Gy irradiation, with collagen deposition, admixed with neutrophilic dermatitis, and necrotic debris. We found that in cultures of normal human keratinocytes, exposure to 17.9 Gy irradiation caused the upregulation of p21/waf1, a marker of senescence. Using western blot analysis of 17.9 Gy-irradiated mice skin samples, we also detected a marker of accelerated senescence (p21/waf1) 7 days post-irradiation, and a marker of cellular apoptosis (activated caspase-3) at 30 days, both preceding histological evidence of inflammatory infiltrates. Immunohistochemistry revealed reduced epithelial stem cells from hair follicles 14-30 days post-irradiation. Furthermore, p21/waf1 expression was increased in the region of the hair follicle stem cells at 14 days post 17 Gy irradiation. These data indicate that radiation induces accelerated cellular senescence in the region of the stem cell population of the skin.


Assuntos
Especificidade de Órgãos/efeitos da radiação , Lesões por Radiação/patologia , Envelhecimento da Pele/efeitos da radiação , Células-Tronco Adultas/efeitos da radiação , Envelhecimento , Animais , Apoptose/efeitos da radiação , Senescência Celular/efeitos da radiação , Modelos Animais de Doenças , Relação Dose-Resposta à Radiação , Feminino , Fibrose , Folículo Piloso/patologia , Folículo Piloso/efeitos da radiação , Queratinócitos/patologia , Queratinócitos/efeitos da radiação , Camundongos Endogâmicos C57BL , Pele/patologia , Pele/efeitos da radiação , Úlcera/patologia
19.
J Radiat Res ; 57 Suppl 1: i2-i10, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27125639

RESUMO

The embryonic brain is radiation-sensitive, with cognitive deficits being observed after exposure to low radiation doses. Exposure of neonates to radiation can cause intracranial carcinogenesis. To gain insight into the basis underlying these outcomes, we examined the response of the embryonic, neonatal and adult brain to low-dose radiation, focusing on the neural stem cell compartments. This review summarizes our recent findings. At E13.5-14.5 the embryonic neocortex encompasses rapidly proliferating stem and progenitor cells. Exploiting mice with a hypomorphic mutation in DNA ligase IV (Lig4(Y288C) ), we found a high level of DNA double-strand breaks (DSBs) at E14.5, which we attribute to the rapid proliferation. We observed endogenous apoptosis in Lig4(Y288C) embryos and in WT embryos following exposure to low radiation doses. An examination of DSB levels and apoptosis in adult neural stem cell compartments, the subventricular zone (SVZ) and the subgranular zone (SGZ) revealed low DSB levels in Lig4(Y288C) mice, comparable with the levels in differentiated neuronal tissues. We conclude that the adult SVZ does not incur high levels of DNA breakage, but sensitively activates apoptosis; apoptosis was less sensitively activated in the SGZ, and differentiated neuronal tissues did not activate apoptosis. P5/P15 mice showed intermediate DSB levels, suggesting that DSBs generated in the embryo can be transmitted to neonates and undergo slow repair. Interestingly, this analysis revealed a stage of high endogenous apoptosis in the neonatal SVZ. Collectively, these studies reveal that the adult neural stem cell compartment, like the embryonic counterpart, can sensitively activate apoptosis.


Assuntos
Células-Tronco Adultas/efeitos da radiação , Compartimento Celular/efeitos da radiação , Células-Tronco Embrionárias Murinas/efeitos da radiação , Células-Tronco Neurais/efeitos da radiação , Radiação Ionizante , Células-Tronco Adultas/citologia , Animais , Apoptose/efeitos da radiação , Proteínas Mutadas de Ataxia Telangiectasia/deficiência , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Quebras de DNA de Cadeia Dupla/efeitos da radiação , DNA Ligase Dependente de ATP/deficiência , DNA Ligase Dependente de ATP/metabolismo , Relação Dose-Resposta à Radiação , Humanos , Camundongos , Camundongos Mutantes , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Neurais/citologia , Síndrome
20.
Stem Cell Res Ther ; 7(1): 54, 2016 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-27086866

RESUMO

The electromagnetic field (EMF) has a great impact on our body. It has been successfully used in physiotherapy for the treatment of bone disorders and osteoarthritis, as well as for cartilage regeneration or pain reduction. Recently, EMFs have also been applied in in vitro experiments on cell/stem cell cultures. Stem cells reside in almost all tissues within the human body, where they exhibit various potential. These cells are of great importance because they control homeostasis, regeneration, and healing. Nevertheless, stem cells when become cancer stem cells, may influence the pathological condition. In this article we review the current knowledge on the effects of EMFs on human adult stem cell biology, such as proliferation, the cell cycle, or differentiation. We present the characteristics of the EMFs used in miscellaneous assays. Most research has so far been performed during osteogenic and chondrogenic differentiation of mesenchymal stem cells. It has been demonstrated that the effects of EMF stimulation depend on the intensity and frequency of the EMF and the time of exposure to it. However, other factors may affect these processes, such as growth factors, reactive oxygen species, and so forth. Exploration of this research area may enhance the development of EMF-based technologies used in medical applications and thereby improve stem cell-based therapy and tissue engineering.


Assuntos
Células-Tronco Adultas/efeitos da radiação , Cartilagem/efeitos da radiação , Condrócitos/efeitos da radiação , Células-Tronco Mesenquimais/efeitos da radiação , Osteoblastos/efeitos da radiação , Regeneração/efeitos da radiação , Células-Tronco Adultas/efeitos dos fármacos , Cartilagem/efeitos dos fármacos , Cartilagem/patologia , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/efeitos da radiação , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/efeitos da radiação , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/efeitos da radiação , Condrócitos/efeitos dos fármacos , Campos Eletromagnéticos , Radiação Eletromagnética , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Espécies Reativas de Oxigênio/farmacologia , Regeneração/efeitos dos fármacos
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